# ARTS built-in documentation server

## Workspace Method ySimpleSpectrometer

### Description

Converts iy to y assuming a fixed frequency resolution.
This is a short-cut, avoiding yCalc, that can be used to convert
monochromatic pencil beam data to spectra with a fixed resolution.
The method mimics a spectrometer with rectangular response
functions, all having the same width (*df*). The position of
the first spectrometer channel is set to f_grid[0]+df/2.
The centre frequency of channels are returned as y_f.
Auxiliary variables and jacobians are not handled.

**Authors: **Patrick Eriksson

### Synopsis

### Variables

OUT | y | (Vector) | The measurement vector. |

OUT | y_f | (Vector) | The frequencies associated with y. |

IN | iy | (Matrix) | Monochromatic pencil beam radiance spectrum. |

IN | stokes_dim | (Index) | The dimensionality of the Stokes vector (1-4). |

IN | f_grid | (Vector) | The frequency grid for monochromatic pencil beam calculations. |

GIN | df | (Numeric) | Selected frequency resolution. |